Mobile email messaging systems typically use a store and forward architecture. Electronic Mail (email) redirector software runs either on an enterprise email server or on a desktop computer. The redirector software monitors a user mailbox. When a new email message is received in the mailbox, the redirector makes a copy of the email message and wraps the copy in an encryption envelope and encapsulates the copy for delivery to the mobile device. The redirector may optionally encrypt and/or digitally sign the encapsulated email message.
The encrypted encapsulated email message is sent out over the Internet and routed to a mobile device associated with the user mailbox. If encrypted, the email message is decrypted by the mobile device prior to being stored on the mobile device and then displayed and stored on the mobile device. This same process is repeated for every new email that is received in the user's mailbox.
Thus, with this architecture two versions of the same mailbox exist. The primary mailbox on the email server or desktop PC, and the replicated mailbox on the mobile device. Consistency between the primary and the replicated mailbox may be maintained to some degree using synchronization messages passing back and forth between the redirector and the mobile device. For example, an email message deleted from the mobile device may result in a synchronization message to the desktop redirector, which instructs it to also delete that message from the primary mailbox. In some versions of this architecture, no effort at all is made to ensure consistency of mailbox state between the primary and replicated instances. This store and forward architecture is cumbersome, does not operate in real-time, and requires sending a large number of email messages over the Internet. The present invention addresses this and other problems associated with the prior art.